FR3150521A1 - MULTI-STAGE POLYMER, PREPARATION METHOD THEREOF, COMPOSITION COMPRISING IT AND USE THEREOF - Google Patents

Abstract

MULTI-STAGE POLYMER, PREPARATION METHOD THEREOF, COMPOSITION COMPRISING THE SAME AND USE THEREOF The present invention relates to a composition comprising a multi-stage polymer, a preparation method therefor, a composition comprising the same and use therefor. In particular, the present invention relates to a composition in the form of a polymer powder comprising a simple multi-stage polymer in the form of polymer particles prepared by a multi-stage process. More particularly, the present invention relates to a polymer composition in the form of a porous polymer powder comprising polymer particles prepared by a multi-stage process comprising two stages and comprising, as an outer shell, a (meth)acrylic copolymer comprising alicyclic hydrocarbon groups, a preparation method therefor, use therefor and compositions and articles comprising the same.

Description

MULTI-STAGE POLYMER, PREPARATION METHOD THEREOF, COMPOSITION COMPRISING IT AND USE THEREOF

The present invention relates to a composition comprising a multi-stage polymer, a method of preparing it, a composition comprising it and its use.

In particular, the present invention relates to a composition in the form of a polymer powder comprising a simple multi-stage polymer in the form of polymeric particles prepared by a multi-stage process.

More particularly, the present invention relates to a polymer composition in the form of a porous polymer powder comprising polymer particles prepared by a multi-step process comprising two steps and comprising, as an outer shell, a (meth)acrylic copolymer comprising alicyclic hydrocarbon groups, its preparation process, its use and compositions and articles comprising it.

[Technical problem]

Polymers are widely used also as additives in polymer compositions. These so-called polymer additives are usually added as granules or also as powders, either to solid polymers, or to molten polymers, or to liquid resins, or to liquid compositions.

One class of polymeric additives is processing aids, another is polymeric impact resistance modifiers.

Polymeric impact modifiers may be in the form of polymeric particles. Typically, these polymeric impact modifiers are in the form of core-shell particles that are prepared by a multi-step process, at least one step comprising a rubber-like polymer. Then these particles are incorporated into the polymers or polymer compositions to increase their impact resistance. The polymers or polymer compositions may be thermosetting or thermoplastic.

Thermosetting polymers consist of cross-linked three-dimensional structures. Cross-linking is achieved by curing reactive groups in the so-called prepolymer. Curing, for example, can be achieved by heating the polymer chains or the prepolymer in order to cross-link and permanently harden the material.

Thermoplastic polymers consist of linear or branched polymers, which are usually not crosslinked. They can be slightly crosslinked as long as they can be deformed by heat. However, these core–shell particles mentioned above are not easy to disperse or fast to disperse in all kinds of resins or polymers or polymer precursors, including for example in liquid epoxy resins or in liquid monomers or in other liquid polymer precursors.

A well homogeneous and rapid dispersion is necessary to have a satisfactory impact resistance performance in the final polymer composition. Easy dispersion and rapid dispersion time are also required to reduce the process time and obtain an easier and simpler process.

An objective of the present invention is to provide a polymer composition which is rapidly and easily dispersible, in particular in liquid resins such as for example precursors for thermosetting polymers or thermoplastic polymers such as respectively for example in epoxy resins or in (meth)acrylic monomers.

An objective of the present invention is to provide a polymer composition in the form of a polymer powder which is rapidly and easily dispersible, in particular in liquid resins such as for example precursors for thermosetting polymers or thermoplastic polymers such as respectively for example in epoxy resins or in (meth)acrylic monomers.

A further objective of the present invention is to provide a polymer composition in the form of a dry polymer powder which is easily dispersible, in particular in weakly polar liquid resins or weakly polar (meth)acrylic monomers.

It is also an object of the present invention to provide a multi-stage polymer composition in the form of a dry polymer powder which is readily dispersible, especially in weakly polar liquid resins or weakly polar (meth)acrylic monomers.

An additional object of the present invention is to provide a multi-stage polymer composition in the form of a dry polymer powder which is readily dispersible in reactive epoxy resins, polyester resins or (meth)acrylic resins/polymers or liquid monomers or resins.

Another object of the present invention is to provide a simplified process for the preparation of a multi-step polymer composition in the form of a polymer powder which is readily dispersible in reactive epoxy resins, polyester resins or (meth)acrylic resins/polymers or liquid monomers or resins, especially in weakly polar liquid resins or weakly polar (meth)acrylic monomers.

Yet another object of the present invention is the use of a polymer composition in the form of a polymer powder for the preparation of a liquid composition comprising precursors for thermosetting polymers or thermoplastic polymers.

Yet another goal is to reduce the dispersion time of a polymer powder in such a liquid composition.

[BACKGROUND OF THE INVENTION] Prior Art

WO2016/102666 discloses a composition comprising a multi-stage polymer and a method of preparing the same. The composition further comprises a (meth)acrylic polymer having a weight average molecular weight of less than 100,000 g/mol. The (meth)acrylic polymer may comprise a functional monomer unit.

WO2016/102682 discloses a multi-stage polymer composition and a method of preparing the same. The multi-stage polymer comprises a final stage comprising a (meth)acrylic polymer having a weight average molecular weight of less than 100,000 g/mol. The (meth)acrylic polymer may comprise a functional monomer unit.

WO2019/012052 discloses a composition comprising a multi-stage polymer and a method of preparing the same. The composition further comprises a (meth)acrylic polymer having a mass average molecular weight between 100,000 g/mol and 1,000,000 g/mol. The (meth)acrylic polymer may comprise a functional monomer unit.

Patent application PCT/EP2022/087285 discloses a composition comprising a multi-stage polymer composition and a method for preparing the same. The multi-stage polymer comprises two shells, each comprising monomer units comprising an alicyclic hydrocarbon group having a carbon number of 3 to 20 or monomer units originating from polymerized comonomers (Mc _b1 ) and (Mc _c1 ) respectively, both comonomers having a Hansen solubility parameter δ _p < 10 MPa ^1/2 .

None of the prior art documents disclose a composition comprising a simple multi-stage polymer having only a shell above the rubber-like polymer, said shell polymer comprising monomeric units comprising an alicyclic hydrocarbon group having a carbon number of 3 to 20.

[Brief description of the invention]

Unexpectedly, it was discovered that a polymer composition (PC1) comprising

(a) a polymer (A1) having a glass transition temperature below 10°C,

(b) a polymer (B1) having a glass transition temperature of at least 60°C, said polymer (B1) representing at least 10% by weight and at most 40% by weight of the composition based on a) and b) only,

component a) and component b) of the composition (PC1) are part of a multi-stage polymer (MP1) and the polymer (B1) has a mass average molecular weight Mw between 10,000 g/mole and 500,000 g/mole,

characterized in that the polymer (B1) comprises polymerized monomer units comprising an alicyclic hydrocarbon group having a carbon number of 3 to 20; makes it possible to obtain a polymer composition which can be easily dispersed in weakly polar liquid compositions and giving a liquid composition having a lower viscosity compared to a liquid composition having a polymer composition not comprising monomer units comprising an alicyclic hydrocarbon group having a carbon number of 3 to 20 or compared to a liquid composition having a polymer composition comprising two or more steps or layers comprising monomer units comprising an alicyclic hydrocarbon group having a carbon number of 3 to 20.

Surprisingly, it was also discovered that a process for the preparation of the polymer composition (PC1) in the form of a polymer powder comprising the steps of

a) polymerization by emulsion polymerization of a monomer or a mixture of monomers (A _m ) to obtain a layer in a step (A) comprising the polymer (A1) having a glass transition temperature of less than 10 °C;

b) polymerization by emulsion polymerization of a monomer or a mixture of monomers (B _m ) to obtain a layer in a step (B) comprising a polymer (B1) having a glass transition temperature of at least 60 °C;

d) agglomeration of the composition obtained in steps a) to c);

characterized in that said polymer (B1) represents at least 10% by weight and at most 40% by weight of the composition based on a) and b) only and in that the polymer (B1) has a mass average molecular weight Mw between 10,000 g/mole and 500,000 g/mole and the monomer or mixture of monomers (B _m ) comprises a comonomer (Mc _b1 ), said comonomer (Mc _b1 ) comprises an alicyclic hydrocarbon group having a number of carbons from 3 to 20; provides a polymer composition which can be readily dispersed in a low polar polymer matrix material for thermosetting polymers or thermoplastic polymers or their respective precursors in the form of resins and/or liquid monomers and also provides a liquid composition having a lower viscosity compared to a liquid composition having a polymer composition not comprising monomer units comprising an alicyclic hydrocarbon group having a carbon number of 3 to 20 or compared to a liquid composition having a polymer composition comprising two or more steps or layers comprising monomer units comprising an alicyclic hydrocarbon group having a carbon number of 3 to 20.

Surprisingly, it was also discovered that a process for the manufacture of a liquid polymer composition LPC1 comprising the steps of

(a) supply of said polymeric composition (PC1),

b) bringing the polymeric composition (PC1) into contact with a liquid composition (LC1),

allows to obtain a liquid polymer composition where the polymer composition (PC1) is dispersed homogeneously and rapidly in the liquid composition LC1.

Surprisingly, it was also discovered that a process for the manufacture of a liquid polymer composition LPC1 comprising the steps of

(a) providing said polymeric composition (PC1) in the form of a porous polymer powder having a total intruded volume of at least 1.2 ml/g as measured by mercury porosimetry,

b) bringing the polymeric composition (PC1) into contact with a liquid composition (LC1),

allows to obtain a liquid polymer composition where the polymer composition (PC1) is dispersed homogeneously and rapidly in the liquid composition LC1.

According to a first aspect, the present invention relates to a polymer composition (PC1) comprising

(a) a polymer (A1) having a glass transition temperature below 10°C,

(b) a polymer (B1) having a glass transition temperature of at least 60°C, said polymer (B1) representing at least 10% by weight and at most 40% by weight of the composition based on a) and b) only,

component a) and component b) of the composition (PC1) are part of a multi-stage polymer (MP1) and the polymer (B1) has a mass average molecular weight Mw between 10,000 g/mole and 500,000 g/mole,

characterized in that the polymer (B1) comprises polymerized monomer units comprising an alicyclic hydrocarbon group comprising an alicyclic hydrocarbon group having a carbon number of 3 to 20 .

According to a second aspect, the present invention relates to a method for the preparation of a polymer composition (PC1) comprising the steps of

a) polymerization by emulsion polymerization of a monomer or a mixture of monomers (A _m ) to obtain a layer in a step (A) comprising the polymer (A1) having a glass transition temperature of less than 10 °C,

b) polymerization by emulsion polymerization of a monomer or a mixture of monomers (B _m ) to obtain a layer in a step (B) comprising a polymer (B1) having a glass transition temperature of at least 60 °C,

characterized in that said polymer (B1) represents at least 10% by weight and at most 40% by weight of the composition based on a) and b) only, and in that the polymer (B1) has a mass average molecular weight Mw between 10,000 g/mole and 500,000 g/mole and the monomer or mixture of monomers (B _m ) comprises a comonomer (Mc _b1 ), said comonomer (Mc _b1 ) comprises an alicyclic hydrocarbon group having a number of carbons from 3 to 20 .

In a third aspect, the present invention relates to a method for the preparation of the polymer composition (PC1) in the form of a polymer powder comprising the steps of

a) polymerization by emulsion polymerization of a monomer or a mixture of monomers (A _m ) to obtain a layer in a step (A) comprising the polymer (A1) having a glass transition temperature of less than 10 °C;

b) polymerization by emulsion polymerization of a monomer or a mixture of monomers (B _m ) to obtain a layer in a step (B) comprising a polymer (B1) having a glass transition temperature of at least 60 °C;

c) agglomeration of the composition obtained in steps a) to b);

characterized in that said polymer (B1) represents at least 10% by weight and at most 40% by weight of the composition based on a) and b) only, and in that the polymer (B1) has a mass average molecular weight Mw between 10,000 g/mole and 500,000 g/mole and the monomer or mixture of monomers (B _m ) comprises a comonomer (Mc _b1 ), said monomer (Mc _b1 ) comprises an alicyclic hydrocarbon group comprising a number of carbons from 3 to 20 .

In a fourth aspect, the present invention relates to the use of a polymer composition (PC1) as an impact resistance modifier.

In a fifth aspect, the present invention relates to the use of a polymer composition (PC1) as a composition with reduced dispersion time.

In a sixth aspect, the present invention relates to a method for reducing the dispersion time of a polymer powder in a weakly polar liquid composition using the polymer composition (PC1) in the form of a polymer powder.

In a seventh aspect, the present invention relates to a polymer composition PC2 comprising the polymer composition (PC1) as an impact resistance modifier.

In an eighth aspect, the present invention relates to a method for reducing the dispersion time of a polymeric composition (PC1) in a liquid composition comprising the steps of:

a) providing said polymeric composition (PC1) of the first aspect in the form of a porous polymer powder POW1 having a total intruded volume of at least 1.2 ml/g as measured by mercury porosimetry,

b) bringing the polymeric composition (PC1) into contact with a liquid composition LC1.

According to a ninth aspect, the present invention relates to a liquid polymer composition LPC1 comprising:

a) a polymeric composition (PC1) of the first aspect and

b) a liquid composition (LC1).

The term “polymer powder” as used herein means a polymer in the form of a powder comprising powder grains of the order of at least 1 µm, said powder grains being obtained by agglomeration of primary polymer particles comprising a polymer or polymers, said primary polymer particles being of the order of a nanometer.

The term “primary particle” as used herein refers to a spherical polymer particle comprising a particle of the order of nanometers. Preferably, the primary particle has a weight average particle size between 20 nm and 800 nm.

The term "particle size" as used herein means the volume average diameter of a particle considered to be spherical.

The term "thermoplastic polymer" as used herein means a polymer that is converted to a liquid or becomes more liquid or less viscous when heated and that can be formed into new shapes by the application of heat and pressure.

The term "thermosetting polymer" as used herein means a prepolymer in a flexible, solid or viscous state which irreversibly transforms into an infusible and insoluble polymer network upon curing.

The term "copolymer" as used means that the polymer is made up of at least two different monomer units.

A “multi-stage polymer” as used herein means a polymer formed sequentially by a multi-stage polymerization process. A multi-stage emulsion polymerization process is preferred in which the first polymer is a first-stage polymer and the second polymer is a second-stage polymer, i.e., the second polymer is formed by emulsion polymerization in the presence of the first emulsion polymer, with at least two stages that are different in composition.

The term “(meth)acrylic” as used herein refers to all kinds of acrylic and methacrylic monomers.

The term “(meth)acrylic polymer” as used means that the (meth)acrylic polymer essentially comprises polymers comprising (meth)acrylic monomers which represent 50% by weight or more of the (meth)acrylic polymer.

The term “dry” as used means that the residual water content is less than 1.5% by weight and preferably less than 1.2% by weight.

By specifying that a range is from x to y in the present invention, it means that the upper limit and the lower limit of this range are included, which is equivalent to at least x and up to y.

By specifying that a range is between x and y in the present invention, it means that the upper limit and the lower limit of this range are excluded, which is equivalent to more than x and less than y.

The term "total intruded volume" as used means the total volume into which liquid mercury is introduced according to ISO 15901-1:2016. This volume is cumulative and the analysis results show a cumulative intruded volume in ml/g (cm ³ /g) as a function of the applied pressure or pore diameter. The total intruded volume is the intruded volume at the maximum applied pressure, which also corresponds to the smallest pores.

The term "incremental intrusion" as used refers to the intruded volume in ml/g between two certain pressures or between two pore dimensions. This incremental intrusion can also be expressed relative to the total intruded volume in % by volume.

By "readily dispersed in liquid resins" is meant that a homogeneous dispersion is obtained. The distribution of the polymer composition (PC1) is not homogeneous if separation occurs after initial homogenization.

The term "weakly polar" as used herein refers to compounds having a Hansen solubility parameter δ _p < 10 MPa ^1/2 . Hansen solubility parameters reflect the physicochemical dissolution properties, also called solvation abilities, of organic substances. Hansen solubility parameters can be calculated using the approach proposed by Charles Hansen in the work entitled "Hansen Solubility Parameters: A user's handbook", Second Edition (2007) Boca Raton, Fla.: CRC Press. ISBN 978-0-8493-7248-3. According to this approach, three parameters, called "Hansen parameters": δ _d , δ _{p ,} and δ _h are sufficient to predict the behavior of a solvent with respect to a given molecule. The parameter δ _d in MPa ^1/2 , quantifies the energy of the dispersion forces between molecules, i.e., the van der Waals forces. The parameter δ _p in MPa ^1/2 represents the energy of the intermolecular dipolar interactions. Finally, the parameter δ _h in MPa ^1/2 , quantifies the energy resulting from the intermolecular hydrogen bonds, i.e., the ability to interact through a hydrogen bond. The sum of the squares of the three parameters corresponds to the square of the Hildebrand solubility parameter (δ _tot ).

By rapidly dispersed in liquid resins is meant that a homogeneous dispersion is obtained significantly more quickly than with a polymer composition not having the specific composition and molecular weight of the polymer (B1).

Regarding the polymer composition (PC1) according to the invention, it may be in a first embodiment in the form of a polymer powder (POW1), also called polymer powder POW1, comprising a) the polymer (A1) having a glass transition temperature of less than 10 °C, b) the polymer (B1) having a glass transition temperature of at least 60 °C, said polymer (B1) representing at least 10% by weight and at most 40% by weight of the composition based on a) and b) only; component a) and component b) of the composition (PC1) are part of a multi-stage polymer (MP1) and the polymer (B1) has a mass average molecular weight Mw between 10,000 g/mol and 500,000 g/mol and the polymer (B1) comprises polymerized monomer units comprising an alicyclic hydrocarbon group having a carbon number of 3 to 20.

Component b) represents at least 10% by weight of a composition based on a) and b). Preferably, component b) represents at least 15% by weight of the composition based on a) and b) and more preferably at least 20% by weight.

Component b) represents at most 40% by weight of a composition based on a) and b). Preferably component b) represents at most 35% by weight of the composition based on a) and b) and more preferably at most 33% by weight.

In a first advantageous embodiment, component b) represents less than 30% by weight of a composition based on a) and b).

In a second advantageous embodiment, component b) represents less than 32% by weight of a composition based on a) and b).

In a third advantageous embodiment, component b) represents less than 33% by weight of a composition based on a) and b).

Preferably, component b) represents more than 20% by weight of a composition based on a) and b). More preferably, component b) represents more than 21% by weight of the composition based on a) and b).

In a first advantageous embodiment, component b) represents more than 22% by weight of a composition based on a) and b).

In a second advantageous embodiment, component b) represents more than 23% by weight of a composition based on a) and b).

In a third advantageous embodiment, component b) represents more than 25% by weight of a composition based on a) and b).

The respective upper and lower limits given in the preceding paragraphs for the quantity of component (b) may be combined in any combinations of an upper limit and a lower limit.

Preferably component b) represents between 20% by weight and 35% by weight of the composition based on a) and b). More preferably, component b) represents between 25% by weight and 35% by weight of the composition based on a) and b).

In a first advantageous embodiment, component b) represents between 26% by weight and 35% by weight of a composition based on a) and b).

In a second advantageous embodiment, component b) represents between 26% by weight and 34% by weight of a composition based on a) and b).

In a third advantageous embodiment, component b) represents between 26% by weight and 33% by weight of a composition based on a) and b).

Component a) and component b) of the composition (PC1) are part of a multi-stage polymer (MP1).

At least component a) and component b) are obtained by a multi-step process comprising at least two steps respectively (A) and (B); and these two polymers (A1) and (B1) form a multi-step polymer (MP1).

As for the polymer powder (POW1) , it has a volume median particle size D50 between 1 µm and 700 µm. Preferably, the volume median particle size of the polymer powder is between 10 µm and 600 µm, more preferably between 15 µm and 550 µm and advantageously between 20 µm and 500 µm.

The D10 of the volume particle size distribution is at least 10 µm and preferably 15 µm, more preferably 20 µm.

The D90 of the volume particle size distribution is at most 1000 µm and preferably 950 µm, more preferably at most 925 µm and even more preferably at most 900 µm.

The porosity of the polymer composition (PC1) in the form of a polymer powder (POW1) is expressed as total intruded volume or total cumulative intrusion (cumulative intruded volume) in milliliters (ml) of mercury per mass (g) of said polymer powder (POW1). This is measured according to ISO 15901-1: Evaluation of pore size distribution and porosity of solid materials by mercury porosimetry and gas adsorption - Part 1: Mercury porosimetry. Preferably the porous polymer powder (POW1) of the invention has a total intruded volume or total cumulative intrusion of at least 1.2 ml/g, preferably 1.23 ml/g, more preferably 1.26 ml/g, even more preferably 1.30 ml/g. The total cumulative intrusion is taken into account up to a pore size diameter of 0.005 µm. Preferably the total intruded volume or total cumulative intrusion is considered between a pore size diameter of 100 µm and 0.005 µm or a pressure between 0.01 MPa and 400 MPa.

The porous polymer powder (POW1) of the invention has a total intrusion volume or total cumulative intrusion of at most 10 ml/g. Preferably the total intrusion volume is at most 8 ml/g, more preferably at most 7 ml/g, even more preferably at most 6 ml/g, advantageously at most 5 ml/g, more advantageously at most 4 ml/g and most advantageously at most 3.5 ml/g.

The respective upper and lower limits given in the two preceding paragraphs for the total intruded volume or the total cumulative intrusion of the porous polymer powder (POW1) of the invention, may be combined in any combinations of an upper limit and a lower limit.

Preferably the porous polymer powder (POW1) of the invention has a total intrusion volume or total cumulative intrusion of between 1.2 ml/g and 10 ml/g, more preferably between 1.23 ml/g and 8 ml/g, even more preferably between 1.23 ml/g and 7 ml/g, advantageously between 1.23 ml/g and 6 ml/g, more advantageously between 1.23 ml/g and 5 ml/g and more advantageously between 1.26 ml/g and 4 ml/g and most advantageously between 1.30 ml/g and 3.5 ml/g.

Incremental intrusion (incremental intrusion volume) is the volume between two certain pore diameters. Incremental intrusion can be expressed as an absolute value also in ml/g or as a relative value as a percentage of total intrusion volume or total cumulative intrusion (which is considered between a pore size diameter of 100 µm and 0.005 µm).

Preferably the porous polymer powder (POW1) of the invention has a cumulative intrusion for a pore size greater than 10 µm (greater than 10 µm) of at least 0.9 ml/g, more preferably at least 1 ml/g.

Preferably the porous polymer powder (POW1) of the invention has an incremental intrusion between a pore size of 10 µm to 1 µm of at least 0.1 ml/g, more preferably at least 0.12 ml/g and even more preferably at least 0.15 ml/g.

The bulk apparent density of the polymer powder (POW1) is less than 0.60 g/cm ³ . Preferably the bulk apparent density is less than 0.45 g/cm ³ , more preferably less than 0.43 g/cm ³ , and even more preferably less than 0.41 g/cm ³ .

The bulk apparent density of the polymer powder (POW1) is greater than 0.1 g/cm ³ . Preferably the bulk apparent density is greater than 0.11 g/cm ³ , more preferably is greater than 0.12 g/cm ³ , even more preferably greater than 0.13 g/cm ³ .

The bulk apparent density of the polymer powder (POW1) is between 0.1 g/cm ³ and 0.60 g/cm ³ . Preferably the bulk apparent density of the polymer powder (POW1) is between 0.15 g/cm ³ and 0.45 g/cm ³ . Advantageously the bulk apparent density of the polymer powder POW1 is between 0.2 g/cm ³ and 0.4 g/cm ³ .

The respective preferred embodiment of all different features of the porous polymer powder (POW1), can be combined in any combination.

Regarding the polymer composition (PC1) according to the invention, according to a second embodiment, it can be dispersed in a continuous phase, comprising a) the polymer (A1) having a glass transition temperature of less than 10 °C, b) the polymer (B1) having a glass transition temperature of at least 60 °C; component a) and component b) of the composition (PC1) are part of a multi-stage polymer (MP1) and the polymer (B1) has a mass average molecular weight Mw between 10,000 g/mol and 500,000 g/mol and the polymer (B1) comprises monomer units comprising an alicyclic hydrocarbon group having a carbon number of 3 to 20; and c) a liquid composition LC1 as a continuous phase in which the polymer composition (PC1) is dispersed.

The multi-stage polymer (MP1) of the composition (PC1) according to the invention has at least two stages respectively (A) and (B); and these two stages, respectively comprising the polymer (A1) and the polymer (B1) are different with respect to their polymer composition.

The multi-stage polymer (MP1) is preferably in the form of PAR polymer particles. These PAR particles are also called core-shell particles. For example, the first stage comprising the polymer (A1) forms the core, the second or all subsequent stages form the respective shells. Such a multi-stage polymer (MP1), which is also called a core-shell particle, is preferred. If the multi-stage polymer (MP1) comprises only the polymer (A1) and the polymer (B1), it is a core-shell particle comprising only a shell.

In a first preferred embodiment, the multi-stage polymer (MP1) consists of the polymer (A1) forming the core and the polymer (B1) forming the shell, it is a core-shell particle comprising only a shell.

In a second preferred embodiment, the multi-stage polymer (MP1) consists of a seed, forming the core together with the polymer (A1), and the polymer (B1) forming the shell, it is a core-shell particle comprising only a shell.

The PAR particles, included in the polymer composition (PC1) in the form of a polymer powder (POW1) according to one embodiment or dispersed according to another embodiment, are the primary particles.

The PAR particles have a weight average particle size between 15 nm and 900 nm. Preferably, the weight average particle size of the polymer particle is between 20 nm and 800 nm, more preferably between 25 nm and 600 nm, even more preferably between 30 nm and 550 nm, again, even more preferably between 35 nm and 500 nm, preferably between 40 nm and 400 nm, even more preferably between 75 nm and 350 nm, and preferably between 80 nm and 300 nm.

According to a first preferred embodiment, the primary polymer particles PAR are agglomerated and give the polymer composition (PC1) or a part of the polymer composition (PC1). In this case, the polymer composition (PC1) of the invention is in the form of a polymer powder, as described above.

The polymer composition (PC1) according to the invention comprises a multi-stage polymer (MP1) comprising at least a) one stage (A) comprising a polymer (A1) having a glass transition temperature of less than 10°C and at least b) one stage (B) comprising a polymer (B1) having a glass transition temperature of greater than 60°C.

In a first preferred embodiment, step (A) is the first step of said at least two steps and step (B) comprising the polymer (B1) overlaps step (A) comprising the polymer (A1).

In a second preferred embodiment, a seed could also be added before step (A), such that step (A) and the seed would be considered together as the first step and step (b) comprising the polymer (B1) overlaps step (A) comprising the seed and the polymer (A1).

In a third preferred embodiment, step (A) is the first of the two steps and step (B) comprising polymer (B1) overlaps step (A) comprising polymer (A1) and the multi-step polymer (MP1) consists of step (A) comprising polymer (A1) and step (B) comprising polymer (B1) .

Step (B) occurs after step (A). More preferably, step (B) is the last step and polymer (B1) is the outer shell of the multi-step polymer (MP1).

In a first embodiment, the polymer (A1) having a glass transition temperature of less than 10 °C comprises at least 50% by weight of polymer units originating from an alkyl acrylate or alkyl acrylates and the step (A) is the innermost layer of the polymer particle having the multilayer structure. In other words, the step (A) comprising the polymer (A1) is the core of the polymer particle.

As regards the polymer (A1) of the first preferred embodiment, this is a (meth)acrylic polymer comprising at least 50% by weight of polymeric units originating from acrylic monomers. Preferably, 60% by weight and more preferably 70% by weight of the polymer (A1) are acrylic monomers.

The acrylic monomer in the polymer (A1) comprises monomers selected from C1-C18 alkyl acrylates or mixtures thereof. More preferably, the acrylic monomer in the polymer (A1) comprises monomers selected from C2-C12 alkyl acrylic monomers or mixtures thereof. Even more preferably, the acrylic monomer in the polymer (A1) comprises monomers selected from C2-C8 alkyl acrylic monomers or mixtures thereof.

The polymer (A1) may comprise a comonomer or comonomers which are copolymerizable with the acrylic monomer, as long as the polymer (A1) has a glass transition temperature of less than 10°C.

The comonomer or comonomers in the polymer (A1) are preferably chosen from (meth)acrylic monomers and/or vinyl monomers.

Most preferably, the acrylic or methacrylic comonomers of the polymer (A1) are selected from methyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, tert-butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate and mixtures thereof, as long as the polymer (A1) has a glass transition temperature of less than 10°C.

In a specific embodiment, the polymer (A1) is a butyl acrylate homopolymer.

More preferably, the glass transition temperature Tg of the polymer (A1) comprising at least 70% by weight of polymeric units originating from C2 to C8 alkyl acrylate is between -100°C and 10°C, even more preferably between -80°C and 0°C and advantageously between -80°C and -20°C and more advantageously between -70°C and -20°C.

In a second preferred embodiment, the polymer (A1) having a glass transition temperature below 10 °C comprises at least 50% by weight of polymer units originating from isoprene or butadiene and the step (A) is the innermost layer of the polymer particle having the multilayer structure. In other words, the step (A) comprising the polymer (A1) is the core of the polymer particle.

As an example, for the polymer (A1) of the core of the second embodiment, there may be mentioned isoprene homopolymers or butadiene homopolymers, isoprene-butadiene copolymers, isoprene copolymers comprising at most 98% by weight of a vinyl monomer and butadiene copolymers comprising at most 98% by weight of a vinyl monomer. The vinyl monomer may be styrene, an alkylstyrene, acrylonitrile, an alkyl (meth)acrylate or butadiene or isoprene. In a preferred embodiment, the core is a butadiene homopolymer.

More preferably, the glass transition temperature Tg of the polymer (A1) comprising at least 50% by weight of polymeric units originating from isoprene or butadiene is between -100°C and 10°C, even more preferably between -90°C and 0°C, advantageously between -80°C and 0°C and most advantageously between -70°C and -20°C.

In a third preferred embodiment, the polymer (A1) is a silicone rubber-based polymer. The silicone rubber is for example a polydimethylsiloxane. More preferably, the glass transition temperature Tg of the polymer (A1) of the second embodiment is between -150 °C and 0 °C, even more preferably between -145 °C and -5 °C, advantageously between -140 °C and -15 °C and more advantageously between -135 °C and -25 °C.

The polymer (A1) having a glass transition temperature of less than 10 °C comprises monomer units, which have been polymerized. The polymer (A1) in general and the respective polymers (A1) of the first, second and third preferred embodiment are prepared from the respective monomer or monomer mixture (A _m ) giving the monomer units composing the polymer (A1).

As regards the polymer (B1) , mention may be made of copolymers comprising monomers comprising double bonds and/or vinyl monomers, at least one of the monomers comprising an alicyclic hydrocarbon group comprising a number of carbons from 3 to 20. Preferably, the polymer (B1) is a (meth)acrylic polymer, which means that at least 50% by weight of the monomer units of the polymer (B1) are (meth)acrylic monomers.

The copolymer (B1) comprises a comonomer (Mc _b1 ), said comonomer (Mc _b1 ) comprising an alicyclic hydrocarbon group having a carbon number of 3 to 20. The comonomer (Mc _b1 ) in the copolymer (B1) may be present between 5% by weight and 50% by weight, preferably between 10% by weight and 40% by weight and more preferably between 20% by weight and 40% by weight.

In a first even more preferred embodiment, the copolymer (B1) comprises between 25% by weight and 35% by weight of comonomer units originating from the comonomer (Mc _b1 ) comprising an alicyclic hydrocarbon group comprising a number of carbons from 3 to 20. The comonomer (Mc _b1 ) comprising an alicyclic hydrocarbon group comprising a number of carbons from 3 to 20 is preferably a (meth)acrylic monomer.

In a second even more preferred embodiment, the copolymer (B1) comprises between 26% by weight and 35% by weight of comonomer (Mc _b1 ) comprising an alicyclic hydrocarbon group having a number of carbons from 3 to 20. The comonomer (Mc _b1 ) is preferably a (meth)acrylic monomer.

In a third even more preferred embodiment, the copolymer (B1) comprises between 26% by weight and 33% by weight of a comonomer (Mc _b1 ) comprising an alicyclic hydrocarbon group having a number of carbons from 3 to 20. The comonomer (Mc _b1 ) is preferably a (meth)acrylic monomer.

Most preferably the other acrylic or methacrylic comonomers (Mc _b2 ) of the polymer (B1) are selected from methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate and mixtures thereof, as long as the copolymer (B1) has a glass transition temperature of at least 60 °C.

Advantageously, the copolymer (B1) comprises at least 50% by weight of monomer units originating from methyl methacrylate as comonomer (Mc _b2 ), more advantageously 60% by weight.

Preferably, the glass transition temperature Tg of the copolymer (B1) is between 60°C and 150°C. The glass transition temperature of the copolymer (B1) is more preferably between 70°C and 140°C, advantageously between 80°C and 130°C and more advantageously between 85°C and 125°C.

Preferably, a part of the copolymer (B1) is grafted onto the polymer prepared in the previous step.

Preferably, the copolymer (B1) is not fully grafted. “Not fully grafted” means that at least 5% by weight of the copolymer (B1) in the multi-stage polymer (MP1) can be solubilized in a solvent of the copolymer (B1) and extracted. Preferably, at least 10% by weight of the copolymer (B1) in the multi-stage polymer (MP1) can be solubilized in a solvent of the copolymer (B1) and extracted.

The copolymer (B1) having a glass transition temperature of at least 60 °C comprises monomer units, which have been polymerized. The copolymer (B1) in general and in the respective embodiments is prepared from the respective monomers or monomer mixtures (B _m ) comprising the comonomers (Mc _b1 ) and (Mc _b2 ), giving after polymerization the copolymer (B1) with the polymerized monomer units composing the copolymer (B1).

Preferably, the copolymer (B1) does not comprise fragments originating from chain transfer agents, in particular mercaptan-based chain transfer agents.

As regards the polymer (B1) or the extractable part of the polymer (B1) , it has a mass average molecular weight Mw between 10,000 g/mole and 500,000 g/mole.

The polymer (B1) has a mass average molecular weight Mw greater than 10,000 g/mole, preferably greater than 10,500 g/mole, more preferably greater than 11,000 g/mole, even more preferably greater than 12,000 g/mole, advantageously greater than 13,000 g/mole, more advantageously greater than 14,000 g/mole and even more advantageously greater than 15,000 g/mole.

The polymer (B1) or the extractable portion of the polymer (B1 ) has a mass average molecular weight Mw of less than 500,000 g/mole, preferably less than 450,000 g/mole, more preferably less than 400,000 g/mole, even more preferably less than 400,000 g/mole, advantageously less than 350,000 g/mole, more advantageously less than 300,000 g/mole and even more advantageously less than 250,000 g/mole and most advantageously less than 200,000 g/mole.

Preferably, the mass average molecular weight Mw of the polymer (B1) or of the extractable part of the polymer (B1) is between 10,500 g/mole and 450,000 g/mole, more preferably between 11,000 g/mole and 400,000 g/mole and even more preferably between 12,000 g/mole and 350,000 g/mole, advantageously between 13,000 g/mole and 300,000 g/mole, more advantageously between 14,000 g/mole and 250,000 g/mole and most advantageously between 15,000 g/mole and 200,000 g/mole.

In a first advantageous embodiment, the mass average molecular weight Mw of the (meth)acrylic polymer (B1) or of the extractable part of the polymer (B1) is between 10,500 g/mole and 200,000 g/mole, more preferably between 11,000 g/mole and 190,000 g/mole and even more preferably between 12,000 g/mole and 180,000 g/mole, advantageously between 13,000 g/mole and 150,000 g/mole, more advantageously between 14,000 g/mole and 135,000 g/mole and most advantageously between 15,000 g/mole and 120,000 g/mole.

In a second advantageous embodiment, the mass average molecular weight Mw of the (meth)acrylic polymer (B1) or of the extractable part of the polymer (B1) is between 15,000 g/mole and 450,000 g/mole, more preferably between 15,500 g/mole and 400,000 g/mole and even more preferably between 16,000 g/mole and 350,000 g/mole, advantageously between 16,500 g/mole and 300,000 g/mole, more advantageously between 17,000 g/mole and 250,000 g/mole and most advantageously between 17,000 g/mole and 200,000 g/mole.

Preferably, the polymer (B1) or the extractable part of the polymer (B1) does not include fragments from chain transfer agents.

Preferably, the polymer (B1) is a copolymer comprising (meth)acrylic monomers, at least one of the monomers comprising an alicyclic hydrocarbon group comprising a number of carbons from 3 to 20.

As regards further the polymer (B1) , mention may be made of copolymers comprising monomers comprising double bonds and/or vinyl monomers, at least one of the monomers comprising an alicyclic hydrocarbon group comprising a number of carbons from 3 to 20. Preferably, the polymer (B1) is a (meth)acrylic copolymer, which means that at least 50% by weight of the monomer units of the polymer (B1) are (meth)acrylic.

In a first preferred embodiment, the monomeric units comprising an alicyclic hydrocarbon group having a carbon number of 3 to 20 are (meth)acrylic monomers.

In a second preferred embodiment, the number of carbons in the alicyclic hydrocarbon group of the monomer units is from 6 to 20.

The monomer units comprising the alicyclic hydrocarbon group are selected from the group consisting of cyclohexyl acrylate, cyclohexyl methacrylate, 4-tert-butylcyclohexyl acrylate, trimethylcyclohexyl acrylate, bornyl acrylate, bornyl methacrylate, norbornyl acrylate, norbornyl methacrylate, isobornyl acrylate, isobornyl methacrylate, fenchyl acrylate, fenchyl methacrylate, dicyclopentanyl acrylate, dicyclopentanyl methacrylate, dicyclopentenyl acrylate, dicyclopentenyl methacrylate, adamantyl acrylate, adamantyl methacrylate, dimethyladamantyl acrylate, dimethyladamantyl methacrylate, cyclodecyl acrylate, cyclodecyl methacrylate and mixtures thereof.

In a first more preferred embodiment, the monomeric unit comprising the alicyclic hydrocarbon group is chosen from isobornyl acrylate.

In a second more preferred embodiment, the monomeric unit comprising the alicyclic hydrocarbon group is chosen from cyclohexyl acrylate.

The respective preferred and advantageous embodiments of all the different features of the polymers (A1) and (B1) and their respective monomers can be combined in any combination.

The multi-stage polymer (MP1) is obtained by a multi-stage process comprising at least two stages. Component a) and component b) of the composition (PC1) are part of a multi-stage polymer (MP1).

Preferably, the polymer (A1) having a glass transition temperature below 10°C prepared during step (A) is prepared before step (B) or is the first step of the multi-step process.

The copolymer (B1) having a glass transition temperature of at least 60°C prepared during step (B) is prepared after step (A) of the multi-step process.

More preferably, the copolymer (B1) having a glass transition temperature of at least 60°C prepared during step (B) is the outer layer of the multi-step polymer.

Additional intermediate steps could exist between step (A) and step (B).

The weight ratio r of the copolymer (B1) of the outer layer included in step (B) relative to the complete polymer particle or multi-step polymer (MP1) is at least 10% by weight, more preferably at least 20% by weight and even more preferably at least 25% by weight.

According to the invention, the ratio r of the external stage (B) comprising the copolymer (B1) relative to the complete polymer particle or the multi-stage polymer (MP1) is at most 40% by weight.

Preferably, the ratio of polymer (B1) to polymer particle or multi-stage polymer (MP1) is between 20 wt% and 35 wt% and more preferably between 25 wt% and 35 wt%.

In a preferred embodiment, the copolymer (B1) having a glass transition temperature of at least 60°C is the outer layer of the primary polymer particle having the multilayer structure, in other words, the multi-stage polymer (MP1).

Preferably, at least a portion of the copolymer (B1) of layer (B) is grafted onto the polymer prepared in the previous layer. If only two steps (A) and (B) comprising polymers (A1) and (B1) respectively are present, a portion of the copolymer (B1) is grafted onto polymer (A1). More preferably at least 25% by weight of polymer (B1) is grafted. The grafting rate can be determined by extraction with a solvent for copolymer (B1) and gravimetric measurement before and after extraction to determine the ungrafted amount.

In a first more preferred embodiment, at least 30% by weight of the polymer (B1) is grafted.

In a second more preferred embodiment, at least 40% by weight of the polymer (B1) is grafted.

In a third more preferred embodiment, at least 50% by weight of the polymer (B1) is grafted.

Preferably, at least a portion of the copolymer (B1) of the layer (B) is extractable. More preferably, at least 30% by weight of the polymer (B1) is extractable.

In a first more preferred embodiment, at least 5% by weight of the polymer (B1) is extractable.

In a second more preferred embodiment, at least 10% by weight of the polymer (B1) is extractable.

In a third more preferred embodiment, at least 15% by weight of the polymer (B1) is extractable.

The glass transition temperature Tg of the respective polymers can be estimated, for example, by dynamic methods such as thermomechanical analysis.

In order to obtain a sample of the respective polymers (A1) and (B1), these can be prepared alone, and not by a multi-step process, to more easily estimate and measure the individual glass transition temperature Tg of the respective polymers of the respective steps. The copolymer (B1) can be extracted to estimate and measure the glass transition temperature Tg and/or the molecular weight.

Preferably, the polymer composition of the invention, if in the form of a powder, does not comprise solvents. “No solvents” means that any solvent present represents less than 1% by weight of the composition. The monomers of the synthesis of the respective polymers are not considered solvents. The residual monomers in the composition represent less than 2% by weight of the composition.

Preferably, the polymer composition according to the invention, if in the form of a powder, is dry. “Dry” means that the polymer composition according to the present invention comprises less than 3% by weight of moisture and preferably less than 1.5% by weight of moisture and, more preferably, less than 1.2% by weight of moisture.

Moisture can be measured by a thermobalance which heats the polymer composition and measures the weight loss.

The composition according to the invention in the form of a powder does not comprise any solvent intentionally added. Any residual monomers from the polymerization of the respective monomers and water are not considered as solvents.

Preferably, the polymer composition (PC1) of the invention comprises less than 1000 ppm of sulfur. This is due to the fact that the polymer (B) preferably does not comprise fragments originating from chain transfer agents, in particular mercaptan-based chain transfer agents. The sulfur content is measured by inductively coupled plasma atomic emission spectrometry (ICP-AES).

More preferably, the polymer composition (PC1) comprises less than 900 ppm sulfur and even more preferably less than 800 ppm.

As regards a first preferred process for the preparation of the polymer composition (PC1) according to the invention, this comprises the steps of

a) polymerization by emulsion polymerization of a monomer or a mixture of monomers (A _m ) to obtain a layer in a step (A) comprising the polymer (A1) having a glass transition temperature of less than 10 °C;

b) polymerization by emulsion polymerization of a monomer or a mixture of monomers (B _m ) to obtain a layer in a step (B) comprising a polymer (B1) having a glass transition temperature of at least 60 °C .

Preferably step a) is carried out before step b).

More preferably, step b) is carried out in the presence of the polymer (A1) obtained in step a).

As regards a second preferred process for the preparation of the polymer composition (PC1) according to the invention in the form of a polymer powder, this comprises the steps of

a) polymerization by emulsion polymerization of a monomer or a mixture of monomers (A _m ) to obtain a layer in a step (A) comprising the polymer (A1) having a glass transition temperature of less than 10 °C;

b) polymerization by emulsion polymerization of a monomer or a mixture of monomers (BA _m ) to obtain a layer in a step (B) comprising a polymer (B1) having a glass transition temperature of at least 60 °C;

c) agglomeration of the composition obtained in steps a) to c).

Preferably, step a) is performed before step b).

More preferably, step b) is carried out in the presence of the polymer (A1) obtained in step a).

Preferably, during step b), no chain transfer agents are used, in particular no mercaptan-based chain transfer agents.

Advantageously, the first preferred method for the preparation of the polymer composition (PC1) according to the invention is a multi-step process which comprises the successive steps of

a) polymerization by emulsion polymerization of a monomer or a mixture of monomers (A _m ) to obtain a layer in a step (A) comprising the polymer (A1) having a glass transition temperature of less than 10 °C;

b) polymerization by emulsion polymerization of a monomer or a mixture of monomers (B _m ) to obtain a layer in a step (B) comprising a polymer (B1) having a glass transition temperature of at least 60 °C;

c) agglomeration of the composition obtained in steps a) to b).

Preferably, steps a), b) and c) are carried out in this order. When emulsion polymerization is used, the polymer composition at the end of the polymerization is obtained as an aqueous dispersion.

Preferably, during step b), no chain transfer agents are used, in particular no mercaptan-based chain transfer agents.

The respective monomers or monomer mixtures (A _m ) and (B _m ) for forming the layers in steps (A) and (B) respectively comprising polymers (A1) and (B1) respectively are the same as those defined above. The monomers or monomer mixtures (A _m ) and (B _m ) comprise the respective monomers which are as monomer units polymerized in the polymer chain of the respective polymers (A1) and (B1). The characteristics of the polymers (A1) and (C1) respectively are the same as those defined above.

The preferred methods for the preparation of the polymer composition (PC1) comprising the multi-stage polymer (MP1) results in the polymer powder (POW1). The polymer powder POW1 is in the form of grains (large particles). The polymer powder grain or particle comprises agglomerated primary polymer particles prepared by a multi-stage process comprising the multi-stage polymer (MP1) or agglomerated primary polymer particles comprising the multi-stage polymer (MP1).

The agglomeration step can be carried out by coagulation or by atomization.

For preferred processes, coagulation is preferred in the agglomeration step.

The aqueous composition comprising the multi-stage polymer (MP1), before the start of coagulation, has a solids content of less than 35% by weight. If the solids content is greater than 35% by weight, water is added to adjust the solids content. Preferably the solids content is less than 34% by weight, more preferably less than 33% by weight and advantageously less than 32% by weight.

The solids content is measured or estimated gravimetrically, by weighing before and after complete evaporation of the water.

In a first preferred embodiment, the solids content of the aqueous composition comprising the multi-stage polymer (MP1) and the polymer (C1), before the start of coagulation, is between 5% by weight and 35% by weight, more preferably between 6% by weight and 34% by weight, even more preferably between 7% by weight and 33% by weight and advantageously between 8% by weight and 32% by weight.

In a second preferred embodiment, the solids content of the aqueous composition comprising the multi-stage polymer (MP1) and the polymer (C1), before the start of coagulation, is between 20% by weight and 35% by weight, more preferably between 20% by weight and 34% by weight, even more preferably between 20% by weight and 33% by weight and advantageously between 20% by weight and 32% by weight.

In a third preferred embodiment, the solids content of the aqueous composition comprising the multi-stage polymer (MP1) and the polymer (C1), before the start of coagulation, is between 5% by weight and 20% by weight, more preferably between 6% by weight and 20% by weight, even more preferably between 7% by weight and 20% by weight and advantageously between 8% by weight and 20% by weight.

In a fourth preferred embodiment, the solids content of the aqueous composition comprising the multi-stage polymer (MP1) and the polymer (C1), before the start of coagulation, is between 10% by weight and 25% by weight, more preferably between 11% by weight and 24% by weight, even more preferably between 12% by weight and 23% by weight and advantageously between 13% by weight and 22% by weight.

In a fifth preferred embodiment, the solids content of the aqueous composition comprising the multi-stage polymer (MP1) and the polymer (C1), before the start of coagulation, is between 15% by weight and 27% by weight, more preferably between 17% by weight and 27% by weight, even more preferably between 19% by weight and 27% by weight and advantageously between 21% by weight and 27% by weight.

Coagulation can be carried out with a salt or with an inorganic acid.

In a first preferred embodiment, the coagulation is carried out with an inorganic acid.

The process for the preparation of the polymer composition (PC1) according to the invention may optionally comprise the additional step e) of drying the polymer composition.

Preferably, after drying step e), the polymer composition comprises less than 3% by weight, more preferably less than 1.5% by weight, advantageously less than 1.2% of moisture or water.

The moisture content of a polymer composition can be measured with a thermobalance.

Drying of the polymer can be carried out in an oven or vacuum oven with heating of the composition for 48 hours at 50°C.

The liquid composition LC1 of the eighth aspect of the invention is a precursor for thermosetting polymers or thermoplastic polymers. It may be a monomer, a mixture of monomers, a polymerizable or curable oligomer, a mixture of a polymerizable or curable oligomer with one or more monomers or a mixture of polymers with one or more monomers which are liquid at 25°C. Preferably, the liquid has a dynamic viscosity of less than 1000 Pa*s, and more preferably between 0.5 mPa*s and 1000 Pa*s. The value of the dynamic viscosity is taken at a shear rate of 1 1/s. The viscosity is measured with a rheometer. The viscosity is measured as a function of the shear rate and, as indicated above, the value at a shear rate of 1 1/s is taken for comparison.

For example, the liquid composition LC1 may be selected from compositions for the preparation of vinyl ester resin, unsaturated polyester resin or epoxy resin; or it may be for example a styrenic monomer or a (meth)acrylic monomer or a corresponding mixture or a liquid composition comprising said monomers.

In one embodiment, the liquid composition LC1 comprises at least one (meth)acrylic monomer (M2a), the (meth)acrylic monomer being selected from cyclohexyl acrylate, cyclohexyl methacrylate, 4-tert-butylcyclohexyl acrylate, trimethylcyclohexyl acrylate, bornyl acrylate, bornyl methacrylate, norbornyl acrylate, norbornyl methacrylate, isobornyl acrylate, isobornyl methacrylate, fenchyl acrylate, fenchyl methacrylate, dicyclopentanyl acrylate, dicyclopentanyl methacrylate, dicyclopentenyl acrylate, dicyclopentenyl methacrylate, adamantyl acrylate, adamantyl methacrylate, dimethyladamantyl acrylate, dimethyladamantyl methacrylate, cyclodecyl, cyclodecyl methacrylate or mixtures thereof. Preferably, the polymeric composition (PC1) represents between 0.5% by weight and 50% by weight of the composition comprising the liquid composition LC1 and the polymeric composition (PC1), more preferably between 0.5% by weight and 40% by weight, even more preferably between 1% by weight and 30% by weight.

In one embodiment, the liquid composition (LC1) comprises

a) the polymer composition (PC1) and

b) a monomer (M2a),

the weight ratio of the polymer composition (PC1) to the monomer (M2a) in the liquid composition LC1 being between 1/99 and 25/75.

Preferably, the monomer (M2a) is a (meth)acrylic monomer.

The present invention also relates to the use of the polymer composition (PC1) in the form of the polymer powder according to the invention as an impact resistance modifier in polymers, in order to obtain a polymer composition with modified impact resistance. Preferably, the polymers are thermosetting polymers or thermoplastic polymers or their precursors.

The present invention also relates to the use of the polymer composition (PC1) in the field of compositions for UV curing, 3D printing, adhesives, structural adhesives, coatings, solid surfaces, wind energy, composites (thermoplastic and thermosetting).

[Evaluation methods]

Transition temperature glassy

The glass transitions (Tg) of polymers are measured with an apparatus capable of performing thermomechanical analysis. A RDAII analyzer “RHEOMETRICS DYNAMIC ANALYSER” supplied by Rheometrics Company was used. Thermomechanical analysis accurately measures the viscoelastic changes of a sample as a function of temperature, stress or strain applied. The apparatus continuously records the deformation of the sample, maintaining the stress fixed, during a controlled temperature variation program.

The results are obtained by plotting the elastic modulus (G'), loss modulus and loss angle as a function of temperature. The Tg is the highest temperature value read in the loss angle curve, when the derivative of the loss angle is equal to zero.

Molecular weight

The mass average molecular weight (Mw) of the polymers is measured by size exclusion chromatography (SEC). Polystyrene standards are used for calibration. The polymer is dissolved in THF at a concentration of 1 g/l. The chromatography column uses a modified silica. The flow rate is 1 ml/min and a refractive index detector is used.

Extraction

The extractable part of the polymer composition is measured gravimetrically. The sample is treated with stirring for 4 hours at 20 °C in THF at 10 g/l. The solution is filtered and after evaporation of the solvent from the filtered solution, the recovered polymer is weighed and its ratio is calculated.

Particle size analysis

The particle size of primary particles after multi-stage polymerization is measured with a Malvern Zetasizer using dynamic light scattering.There volume average particle size (diameter) is taken as the result.

The particle size of the polymer powder after recovery is measured with a MALVERN Malvern Mastersizer 3000 with laser diffraction.

For estimation of volume average powder particle size, particle size distribution and proportion of fine particles, a Malvern Mastersizer 3000 with 300 mm objectives is used, measuring a range of 0.5 to 880 µm.

Apparent density

ISO 60:1977 is used. The sample is purified through a specified funnel into a measuring cylinder with a capacity of 100 cubic centimeters, the excess is removed with an adjuster's rule and the mass of the contents is determined by weighing.

Viscosity

Viscosity can be easily measured with a rheometer or viscometer. Dynamic viscosity is measured at 25°C. If the liquid has Newtonian behavior, meaning that it does not exhibit shear thinning, the dynamic viscosity is independent of shear in a rheometer or of the speed of the spindle in a viscometer. If the liquid composition has non-Newtonian behavior, meaning that it exhibits shear thinning, the dynamic viscosity is compared to a shear rate of 1 s ^-1 at 25°C.

[Examples]

A polymer composition (PC) in the form of a core–shell multi-step polymer comprising a core and two shell layers is prepared according to the method as described in WO2020/260638 for Comparative Example 1. For Comparative Example 2 however, 30 wt% of the MMA in the synthesis of the two shell layers of Comparative Example 1 is replaced by isobornyl acrylate (IBOA).

The two products obtained are coagulated with sulfuric acid and dried.

As Example 1, the following product is prepared: First stage (A) - Polymerization of one type of polymer (A1): Into a 20-liter high-pressure reactor are charged: deionized water 116.5 parts, beef tallow fatty acid potassium salt emulsifier 0.1 part, 1,3-butadiene 21.9 parts, t-dodecyl mercaptan 0.1 part and p-menthane hydroperoxide 0.1 part as initial tank charge. The solution was heated, with stirring, to 43 °C after which a redox catalyst solution was charged (4.5 parts of water, 0.3 parts of sodium tetrapyrophosphate, 0.004 parts of ferrous sulfate and 0.3 parts of dextrose), which effectively initiates the polymerization. The solution was then further heated to 56°C and maintained at this temperature for a period of three hours. Three hours after polymerization was initiated, a second charge of monomer (77.8 parts BD, 0.2 parts t-dodecyl mercaptan), half of an additional charge of emulsifier and reductant (30.4 parts deionized water, 2.8 parts beef tallow fatty acid potassium salt emulsifier, 0.5 parts dextrose), and additional initiator (0.8 parts p-menthane hydroperoxide) were added continuously over a period of eight hours. After the second monomer addition was complete, the remaining charge of emulsifier and reductant and the initiator were added continuously over a period of five additional hours. Thirteen hours after the initiation of polymerization, the solution was heated to 68 °C and allowed to react until at least twenty hours had elapsed since the initiation of polymerization, producing polybutadiene rubber latex. The resulting polybutadiene rubber latex (A1) contained 38% by weight solids and had a weight average particle size of about 160 nm. Second stage (B) - Polymerization of polymer type (B2): Into a 3.9 liter reactor are charged 71 parts, on a solids basis, of polybutadiene rubber latex A1, 37.6 parts of deionized water and 0.1 part of sodium formaldehyde sulfoxylate. The solution was stirred, purged with nitrogen and heated to 77 °C. When the solution reached 77 °C, a mixture of 20.3 parts of methyl methacrylate, 8.7 parts of isobornyl acrylate, and 1 and 0.1 parts of t -butyl hydroperoxide initiator was added continuously over a period of 70 minutes, followed by an 80-minute holding period. Thirty minutes after the start of the holding period, 0.1 part of sodium formaldehyde sulfoxylate and 0.1 part of t -butyl hydroperoxide were added to the reactor at one time. After the 80-minute holding period, a stabilizing emulsion was added to the graft copolymer latex. The stabilizing emulsion was prepared by mixing 3.2 parts deionized water (based on the mass of graft copolymer), 0.1 part oleic acid, 0.1 part potassium hydroxide and 0.9 part octadecyl 3-(3,5-di- tert -butyl-4-hydroxyphenyl)propionate. The resulting core-shell polymer (MP1) had a weight average particle size of about 180 nm. The final multi-stage polymer (MP1) was then recovered by coagulation, the polymer composition being coagulated with sulfuric acid and dried to yield a powder of MP1.

[Table 1] Reference CS report Particle size
[nm] ^1st envelope
Polymer (B1) ^2nd envelope
Polymer (C1) Extracted polymer /[%] Mw of extracted polymer /[g/mole] Comparative example 1 71/29 177 PMMA – cross-linked PMMA – transfer agent 12 35,000 Comparative example 2 71/29 170 PMMA –IBOA (70/30) cross-linked - transfer agent PMMA-IBOA (70/30)- transfer agent 7 18,000 Example 1 71/29 170 PMMA –IBOA (70/30) - 7 19,000

[Table 2]

Table 2 - Powder properties Reference D10 / [µm] D50 / [µm] D90 / [µm] MVA / [g/cm3] pH Porosity /[ml/g] Comparative example 1 64 200 520 0.20 5.6 2.45 Comparative example 2 150 397 848 0.36 6.7 - Example 1 205 454 887 0.35 6.6 -

The two powders of Comparative Example 1 and Example 1 are tested in different concentrations in isobornyl acrylate ( at 10% by weight) and ( at 15% by weight) as monomers. The viscosity in Pa*s is given as a function of the shear rate of 1/s at 25°C. Example 1 is shown in square symbols and comparative example 2 in diamond symbols. The results are shown in Figures 1 and 2.

The viscosity is also compared in Table 3 at a shear rate of 1/s.

[Table 3]

Table 3 – Viscosity Reference 10 wt% in IBOA at a shear rate of 1/s / [mPa*s] 15 wt% in IBOA at a shear rate of 1/s / [mPa*s] Comparative example 1 grains - Comparative example 2 0.167 1.96 Example 1 0.102 1.0

The composition according to the invention and obtained according to the process of the invention makes it possible to obtain a significantly lower viscosity of the liquid compositions. It can be dispersed at a much higher concentration.

Claims (17)

Polymer composition (PC1) comprising
(a) a polymer (A1) having a glass transition temperature below 10°C,
(b) a polymer (B1) having a glass transition temperature of at least 60°C, said polymer (B1) representing at least 10% by weight and at most 40% by weight of the composition based on a) and b) only,
component a) and component b) of the composition (PC1) are part of a multi-stage polymer (MP1) and the polymer (B1) has a mass average molecular weight Mw between 10,000 g/mole and 500,000 g/mole,
characterized in that the polymer (B1) comprises polymerized monomeric units comprising an alicyclic hydrocarbon group having a carbon number of 3 to 20 . Polymer composition (PC1) according to claim 1, characterized in that a portion of the polymer (B1) is grafted onto the polymer (A1). Polymer composition (PC1) according to claim 2, characterized in that at least 25% by weight of the polymer (B1) is grafted. Polymer composition (PC1) according to claim 1, characterized in that at least 5% by weight of the polymer (B1) in the multi-stage polymer (MP1) can be solubilized in a solvent of the copolymer (B1) and extracted. Polymer composition according to claim 1 to 4, characterized in that each of the polymer (B1) does not comprise fragments originating from chain transfer agents, in particular mercaptan-based chain transfer agents. Polymer composition (PC1) according to any one of claims 1 to 5, characterized in that the polymer composition (PC1) comprises less than 1,000 ppm of sulfur. Polymer composition according to any one of claims 1 to 6, characterized in that each of the polymer (B1) comprises between 25% by weight and 35% by weight of monomer units comprising the alicyclic hydrocarbon group comprising a number of carbons from 3 to 20. Polymer composition (PC1) according to any one of Claims 1 to 7, characterized in that the monomer units comprising an alicyclic hydrocarbon group comprising a number of carbons from 3 to 20 are chosen from cyclohexyl acrylate, cyclohexyl methacrylate, 4-tert-butylcyclohexyl acrylate, trimethylcyclohexyl acrylate, norbornyl acrylate, norbornyl methacrylate, isobornyl acrylate, isobornyl methacrylate, fenchyl acrylate, fenchyl methacrylate, dicyclopentanyl acrylate, dicyclopentanyl methacrylate, dicyclopentenyl acrylate, dicyclopentenyl methacrylate, adamantyl acrylate, adamantyl methacrylate, dimethyladamantyl acrylate, dimethyladamantyl methacrylate, cyclodecyl, cyclodecyl methacrylate. Polymeric composition (PC1) according to any one of claims 1 to 8, characterized in that the polymeric composition (PC1) is in the form of a porous polymer powder POW1 having a total intruded volume of at least 1.2 ml/g as measured by mercury porosimetry. A process for the preparation of the polymer composition according to any one of claims 1 to 9 comprising the steps of
a) polymerization by emulsion polymerization of a monomer or a mixture of monomers (A _m ) to obtain a layer in step (A) comprising the polymer (A1) having a glass transition temperature of less than 10 °C;
b) polymerization by emulsion polymerization of a monomer or a mixture of monomers (B _m ) to obtain a layer in step (B) comprising a polymer (B1) having a glass transition temperature of at least 60 °C;
characterized in that said polymer (B1) represents at least 10% by weight and at most 40% by weight of the composition based on a) and b) only, and in that the polymer (B1) has a mass average molecular weight Mw between 10,000 g/mole and 500,000 g/mole and the monomer or mixture of monomers (B _m ) comprises a comonomer (Mc _b1 ), said comonomer (Mc _b1 ) comprises an alicyclic hydrocarbon group comprising a number of carbons from 3 to 20 . A process for the preparation of the polymer composition according to any one of claims 1 to 9 comprising the steps of
a) polymerization by emulsion polymerization of a monomer or a mixture of monomers (A _m ) to obtain a layer in step (A) comprising the polymer (A1) having a glass transition temperature of less than 10 °C;
b) polymerization by emulsion polymerization of a monomer or a mixture of monomers (B _m ) to obtain a layer in step (B) comprising a polymer (B1) having a glass transition temperature of at least 60 °C;
c) agglomeration of the composition obtained in steps a) to b);
characterized in that said polymer (B1) represents at least 10% by weight and at most 40% by weight of the composition based on a) and b) only, and in that the polymer (B1) has a mass average molecular weight Mw between 10,000 g/mole and 500,000 g/mole and the monomer or mixture of monomers (B _m ) comprises a comonomer (Mc _b1 ), said comonomer (Mc _b1 ) comprises an alicyclic hydrocarbon group comprising a number of carbons from 3 to 20 . Method according to claim 11, characterized in that the agglomeration step is carried out by coagulation. Method according to claim 10 or 11, characterized in that during step b), no chain transfer agents are used, in particular no mercaptan-based chain transfer agents. Use of the polymer composition (PC1) according to any one of claims 1 to 9 or obtained by the process according to any one of claims 10 to 13 as an impact resistance modifier. Liquid composition LC1 comprising
a) the polymer composition (PC1) according to any one of claims 1 to 9 or obtained by the process according to any one of claims 10 to 13 and
b) a monomer (M2a)
characterized in that the weight ratio of the polymer composition (PC1) to monomer (M2a) in the liquid composition LC1 is between 1/99 and 25/75. Liquid composition LC1 according to claim 15, characterized in that the monomer (M2) is chosen from cyclohexyl acrylate, cyclohexyl methacrylate, 4-tert-butylcyclohexyl acrylate, trimethylcyclohexyl acrylate, norbornyl acrylate, norbornyl methacrylate, isobornyl acrylate, isobornyl methacrylate, fenchyl acrylate, fenchyl methacrylate, dicyclopentanyl acrylate, dicyclopentanyl methacrylate, dicyclopentenyl acrylate, dicyclopentenyl methacrylate, adamantyl acrylate, adamantyl methacrylate, dimethyladamantyl acrylate, dimethyladamantyl methacrylate, cyclodecyl acrylate, cyclodecyl methacrylate and corresponding mixtures. Use of the polymer composition (PC1) according to any one of claims 1 to 9 or obtained by the process according to any one of claims 10 to 13 in the field of compositions for UV curing, 3D printing, adhesives, structural adhesives, coatings, solid surface, wind energy and composites (thermoplastic and thermosetting).